84 
PLANT-BUGS INJURIOUS TO COTTON BOLLS. 
PENTATOMID BUGS OF THE GENUS THYANTA. 
(Plate I, fig. 4; text figs. 17 and 18.) 
IDENTITY AND HISTORY OF SPECIES CONCERNED. 
The writer has carefully examined a series of over 80 specimens 
which appear to represent a single species of the genus Thyanta and 
finds that the variation is so wide that while the majority are undoubt- 
edly T. custator as described by Fabricius, several agree fairly well 
with the original description of T. perditor Fab. and T. casta Stal. 
Variations are found in size, form of humeral angles, proportionate 
lengths of the segments of the antennae, and color and markings of 
the body, antennae, and wing membranes, 
which might readily be mistaken for spe- 
cific characters. 
These latter two species — if in fact they 
are valid — have not as yet been suffi- 
ciently characterized to distinguish them 
from the variations of the insect gener- 
ally recognized as Thyanta custator Fab. 
Injury to crops by this species a was first 
recorded by Prof. E. D. Sanderson, who 
reported its occurrence in 1903 in unusual 
numbers in northern Texas, where it seri- 
ously injured oats, corn, and sorghum, 
and w T as also found in numbers on milo 
maize and cowpeas. The frequent occurrence of this insect on cotton 
bolls has also been noted by Sanderson. 
DISTRIBUTION. 
Uhler states in regard to the distribution of Thyanta custator that 
the species inhabits upper and lower California, Texas, Arizona, 
Colorado, "Dakota," and the Atlantic region generally from Quebec 
to Florida. 6 According to Mr. Van Duzee, it occurs in greatest 
abundance toward the South and West. c In Texas it is one of the 
most common Pentatomid bugs and is especially abundant in the 
northwestern part of the State. Except in northern Texas and 
Oklahoma, it seems to be of too rare occurrence on cotton to be 
worthy of consideration as a pest. 
°At first determined as Thyanta perditor Fab. and afterwards redetermined as 
T. custator Fab. Compare Bui. 46, Div. Ent., U. S. Dept. Agr., p. 94, 1904, with Bui. 
57, Bur. Ent., U. S. Dept. Agr., p. 49, 1906. 
6 Bui. U. S. Geol. and Geog. Surv., No. 5, Second series, List of Hemiptera, p. 23, 1876. 
c Trans. Amer. Ent. Soc, XXX, p. 53, 1904. 
Fig. 17. — Thyanta custator: Nymph 
first instar. Enlarged 27 diameters 
(Original.) 
